There have been many watches along these lines already, e.g. https://www.empatica.com/en-gb/embrace2/ although previous ones have mostly used motion sensing. This Epilert startup seems to be looking at motion and also other signals like heartbeat, skin temperature, electrodermal activity.

I have a close family member with severe epilepsy so I'm interested, but the usefulness of these devices comes down to reliability and minimising false alarms while also not missing any serious events, which is a very hard thing to get right.

However there's something a little odd about their slogan of "finest epilepsy detection device". I can imagine 'finest' used for chocolate or wine, but its an odd adjective for a medical device.